CN114667397A

CN114667397A - Working cylinder and method for producing the same

Info

Publication number: CN114667397A
Application number: CN202080077626.6A
Authority: CN
Inventors: 约瑟夫·布特
Original assignee: Buemach Engineering International BV
Current assignee: Buemach Engineering International BV
Priority date: 2019-11-08
Filing date: 2020-11-06
Publication date: 2022-06-24
Also published as: DE102019007754A1; WO2021089069A1; EP4055279A1; JP2023502012A; US20220397128A1

Abstract

The invention relates to a working cylinder (1) having a cylinder liner (2), a first closing part (3), a second closing part (4) and a piston unit (5), wherein the cylinder liner (2) has a cylinder liner first end (6) and a cylinder liner second end (7), wherein the first closing part (3) is arranged on the cylinder liner first end (6), wherein the second closing part (4) is arranged on the cylinder liner second end (7), wherein the cylinder liner (2) and the closing parts (3, 4) form a cylinder interior (8), wherein the piston unit (5) forms at least one working chamber in the cylinder interior (8), wherein the piston unit (5) passes through the first closing part (3) in a sliding manner, characterized in that the first closing part (3) and the cylinder liner (2) are locked together by means of an annular first laser ring weld (9) by means of a material The second closing part (4) is connected to the cylinder liner (2) by means of an annular second laser circumferential weld seam (10) in a material-locking manner, and the laser circumferential weld seams (9, 10) each form a fluid-tight sealing plane (10). The invention further relates to a method for producing such a working cylinder.

Description

Working cylinder and method for producing the same

Technical Field

The invention relates to a welded working cylinder and a method for producing the same.

Background

Such a working cylinder is known from the prior art. The working cylinder may be in particular a differential working cylinder, a plunger cylinder, a synchronization cylinder or a telescopic cylinder.

A differential working cylinder is, for example, a double-acting hydraulic working cylinder, which has two working chambers, wherein in the two working chambers there are active surfaces of different piston sizes. Thus, when the operating pressures are the same, forces of different magnitudes act on the piston in the two operating directions. In contrast to the differential operating cylinder, the piston rod is guided in the synchronization cylinder by means of guide closure elements arranged on both sides, so that the active surfaces of the pistons are of the same size and therefore the forces acting in both operating directions are of the same size when the operating pressures are the same, so that the synchronization cylinder is used in particular as a steering cylinder. In contrast, a plunger cylinder is a single-acting working cylinder in which the pressure medium pushes against a piston as a volume and thus causes an extension movement of the piston. These also apply correspondingly to telescopic cylinders, in which a plurality of cylinder bushes present here are pushed into one another and thus a particularly long working movement is possible.

All working cylinders of this type have a cylinder liner as well as a closing member. According to the prior art, the production of these working cylinders is generally carried out by screwing together the closing element and the cylinder liner. Such a working cylinder is therefore also referred to in the prior art as a screwing cylinder.

Furthermore, it is known from the prior art to connect the bottom closure part to the cylinder liner by MAG welding (active gas shielded welding) and then merely screw the guide closure part on.

The threads of the cylinder liner and the closure member are typically formed by a machining process.

According to the prior art, it is possible to provide screw cylinders with high quality and to screw on only one closure part and weld the other closure part on the cylinder with MAG welding (reactive gas welding) and has proven to be a high-quality, reliable product.

In this case, it can be determined on the production side that an additional part of the material thickness, i.e. an additional part of the wall thickness of the bushing, must be assigned to the cylinder bushing, in particular, for the thread to be introduced, which is obtained by subtraction, since the thread inevitably weakens the cylinder bushing. This results in a significantly greater wall thickness of the bushing, which serves to absorb forces during operation, in particular forces generated by the fluid operating pressure. This disadvantageously results in increased material consumption and increased final weight of the differential operating cylinder.

The machining method for forming the thread also disadvantageously requires high precision and thus the demands on production are very high.

In order to achieve a sealing of the cylinder between the cylinder liner and the respective closure part, additional sealing elements are often additionally provided.

In addition, the final assembly also requires a high time input and qualified labor.

A disadvantage is, furthermore, that additional means must be provided to prevent the screw connection from loosening. A final disadvantage is that there are dynamic loads on the thread due to the varying operating pressure, which limits the service life of the thread.

Disclosure of Invention

The object of the invention is to provide a working cylinder which has a very high quality, is material-saving, is simple and can therefore be produced at low cost. The object of the invention is also to provide a cost-effective method for producing such a working cylinder.

The object relating to the working cylinder is achieved by the features cited in claim 1 and the object relating to the production method is achieved by the features cited in claim 10. Preferred variants are given by the respective dependent claims.

According to the invention, the working cylinder has a cylinder liner, a first closing member, a second closing member and a piston unit. The first and second closure parts are also referred to collectively hereinafter as closure parts.

The working cylinder according to the invention, which is formed from these basic components, can be present in different configurations. The working cylinders can be, in particular, differential working cylinders, plunger cylinders, synchronization cylinders, telescopic cylinders, traction cylinders, or likewise pneumatic working cylinders. If the working cylinder is designed as a synchronization cylinder, it is also referred to hereinafter as a steering cylinder. In the context of the present invention, working cylinders are understood to be, in particular, energy storage cylinders, gas spring cylinders and hydraulic dampers.

The cylinder liner is configured in a known manner as a hollow cylinder and has a cylinder liner first end and a cylinder liner second end according to the invention. After assembly is completed, a first closing part is arranged at the first end of the cylinder liner, and a second closing part is arranged at the second end of the cylinder liner. The two cylinder liner ends are preferably produced identically here. The two cylinder liner ends thus preferably have inclined axial end faces, wherein the inclination has the same angle. The axial end faces therefore preferably have the same cross section.

It is also possible to design the cylinder liner ends differently.

According to the invention, the first closing member is arranged on the cylinder liner first end. The first closing member is preferably a guide closing member. The guide closing member refers here to a closing member that slidingly and sealingly accommodates the piston unit. In this case, the piston unit can be formed, for example, by a piston and a piston rod in the differential cylinder, wherein the piston rod is accommodated by the guide closure member. In the plunger cylinder, the piston unit appears as a volume-shaped piston, which is also referred to as a cartridge piston, which is accommodated by a guide closure member.

The first closing part is constructed such that it has a contact surface which, when being attached to the first end of the cylinder liner, abuts against a corresponding further contact surface of the first end of the cylinder liner. These contact surfaces preferably completely surround the first closing part and the cylinder liner. This results in a continuous annular surface against which the first closing element at the first end of the cylinder liner rests. As long as the annular surface is inclined, it appears geometrically as a truncated cone outer surface. In the following, this surface is simply referred to as an annular surface, independently of the geometry, for simplicity.

According to the invention, a second closing member is arranged on the second end of the cylinder liner. The remarks related to the first closing member in relation to the first end of the cylinder liner apply in a corresponding manner to the second closing member in relation to the second end of the cylinder liner. The second closure member is configured similarly to the first closure member with respect to the contact surface. The second closing element is preferably a bottom closing element, which is axially opposite the piston of the piston unit and axially delimits at least one working chamber of the working cylinder according to the invention.

The working cylinder according to the invention furthermore has a piston unit. Depending on the type of working cylinder, the piston unit can be formed by a piston and a piston rod, for example in the case of a differential working cylinder or a synchronous cylinder, or by a single piston, for example in the case of a plunger cylinder, or the piston unit can have another configuration. As long as the piston unit has a piston and a piston rod, the piston and the piston rod are in a fixed positional relationship with respect to each other. The piston and the piston rod are preferably fixedly connected to each other. The connection is preferably designed as a welded connection in a material-locking manner. The piston and the piston rod can likewise be releasably connected. In particular cases, however, it is also possible for the piston unit to be formed in one piece, and for the piston and the piston rod to be sections of a single component.

According to the invention, the cylinder liner and the closing part form a cylinder interior in the assembled state. When the cylinder liner and the closure member are engaged together, their built-in surface sections define the cylinder interior. The cylinder interior opens here to the laser circumferential welds.

Furthermore, in the working cylinder according to the invention, the piston unit forms at least one working chamber in the cylinder interior. The working chamber is defined by a cylinder liner, a closure member and a piston unit. The piston unit is arranged axially displaceable, wherein the main longitudinal axis of the cylinder liner coincides with the axial displacement direction of the piston unit. The piston unit here preferably passes through the first closing part in a sliding, sealing manner and at least in sections. The pressure medium connection is associated with the working chamber, through which pressure medium can be introduced into the working chamber or can be discharged therefrom, and the working chamber can therefore be pressurized. The pressure medium may be a hydraulic pressure medium or a pneumatic pressure medium.

When the working cylinder according to the invention is embodied, for example, in the form of a differential working cylinder, the following applies.

The piston of the piston unit is arranged in the cylinder interior and divides the cylinder interior into a piston bottom working chamber, which is also referred to as piston bottom chamber hereinafter. The piston bottom space is located between the piston and a second closing element, which is designed as a bottom closing element. The piston rod working chamber is located on the piston rod side between the piston and the first closing member, which is here configured as a guide closing member. The at least one working chamber thus acts as a piston rod working chamber. Furthermore, the piston base working chamber forms a further working chamber.

The piston is axially movable and disposed in the cylinder bore such that a major longitudinal axis of the piston overlaps a major longitudinal axis of the cylinder liner.

The pressure medium connection is arranged on the cylinder such that the piston base working chamber and the piston rod working chamber can be acted upon with the operating pressure.

The piston may additionally have different guide rings, sealing rings or piston rings. Different embodiments of such pistons for working cylinders are known from the prior art.

According to the invention, the piston rod is slidingly passed through a first closing member, here configured as a guide closing member.

The piston rod is mounted in a sliding manner in a guide and closure element, wherein the guide and closure element is designed to prevent the outflow of a pressure medium, also referred to as fluid in the following. This is achieved, for example, by means of a corresponding ring seal.

The working cylinder according to the invention is characterized in particular in that the two closing parts, for example the guide closing part and the bottom closing part in the case of a differential working cylinder, are welded to the cylinder liner.

The first closing part is connected to the cylinder liner by means of an annular first laser circumferential weld in a material-locking manner, and the second closing part is connected to the cylinder liner by means of an annular second laser circumferential weld in a material-locking manner. The respectively connected components are also referred to collectively hereinafter as connection partners.

The two closure members are connected to the cylinder liner by laser welding. Laser circumferential welds are fusion welded joints without the addition of welding additional materials.

By laser welding, very narrow, sharp-ended welds are advantageously formed. The tip angle of the spread of the wings of the essentially V-shaped laser weld seam is preferably less than 15 degrees and particularly preferably less than 10 degrees.

The two laser circumferential welds each form a fluid-tight sealing plane. This means that the first laser circumferential weld prevents the pressure medium from penetrating the connection point between the cylinder liner and the first closing part, and the second laser circumferential weld prevents the pressure medium from penetrating the connection point between the cylinder liner and the second closing part, without additional means for sealing, for example a sealing ring.

The cylinder liner and the closing part, and preferably also the piston unit, are each made of a metal alloy, and particularly preferably of a steel alloy. The material composition of the individual components can be easily distinguished here. The mass fraction of the assembly of metal alloys of the cylinder differs from the mass fraction of the assembly of metal alloys of the closure part, preferably by a difference of less than 10 wt.% of the metal alloys of the closure part. The closing part and the cylinder liner therefore have similar physical properties and can be welded to one another particularly well.

The steel alloy used preferably has a carbon content of less than 0.5 wt.%. The components vanadium, chromium and manganese contained in the alloy, individually or in combination, preferably have a proportion of 0.01 to 2 wt.%.

The welded working cylinder according to the invention has a series of considerable advantages compared to the working cylinders of the prior art.

A first significant advantage is that, in particular, no machining of the cylinder liner is required or required at all, except for cutting. Whereby especially no thread cutting or groove turning is necessary. This applies correspondingly also to the piston rod in the welded piston unit.

The direct advantage thereof is firstly that the otherwise necessary expenditure of time, machining machinery, tool costs and energy for the cutting process can be dispensed with.

Furthermore, there is the advantage of a very significant material saving and thus the advantage of a protection of the raw material resources, since the cylinder liner only has to have approximately half the wall thickness of the liner of the screwed differential working cylinder. An additional part, for example in the wall thickness of the bushing, for counteracting the material removal of the thread for cutting can be dispensed with.

By dispensing with a cutting operation of the cylinder liner and preferably also of the piston rod, the quality is furthermore greatly increased. Since the input of force by the cutting work is eliminated, the accuracy of the coaxiality in the axial direction of the starting product is no longer impaired. More precisely, the accuracy of the coaxiality in the axial direction of the starting product for the cylinder liner and, in certain cases, of the piston rod remains completely unchanged. The working cylinder according to the invention has a high precision. Thereby, an axial movement of the piston rod can likewise be provided without the bending problems of the piston rod during the final impact as known from the prior art. Thereby simultaneously reducing wear of the cylinder guide in the guide closing member. By dispensing with cutting machining of the cylinder liner and, in certain cases, of the piston rod, at the same time the load capacity is prevented from being impaired by notch stress concentration effects.

Another advantage is the absolute tightness of the differential working cylinder at the connection point between the cylinder liner and the closing member. It is additionally advantageous here that this tightness is achieved without further seals being necessary according to the prior art. These components which are subject to ageing can be dispensed with, which, in addition to saving costs, also leads to improved quality and increased service life. This eliminates the contamination problem caused by aged seals.

Another advantage resides in improved operational safety and reliability. When, for example, the load on the thread changes or loosens, there is no axial movement space which may occur between the cylinder liner and the closure part, as in the thread. In addition, savings are advantageously achieved by dispensing with further necessary safety elements. Finally, the other necessary fastening of the actual securing element, which is necessary in the releasable connection, is likewise dispensed with. According to the prior art, such a fixing is achieved, for example, by gluing the securing elements together. While eliminating adhesion is associated with other important advantages. First, the cost of the very expensive bolt fuse adhesive is eliminated. Secondly, cleaning of the surfaces for producing the adhesive bond of the screw securing element is dispensed with, whereas according to the prior art generally healthy, problematic chemicals are necessary. Special measures for ensuring health protection and for ensuring environmental protection are thereby dispensed with. Thirdly, the problem that a releasable connection fixed by means of a bolt securing adhesive may run the risk of loosening in the event of impact loads is overcome.

As an aspect of the improved operational safety, the improved operational safety is also to be said. Non-destructive interference in the cylinder bore is eliminated. The source of damage caused by untrained personnel associated with incorrect opening of the differential cylinders, or the possible source of damage caused by untrained personnel associated with incorrect re-fitting of the cylinders, is not present.

By means of the laser welding method, only a strictly locally defined temperature rise of the material occurs in the region of the laser girth weld. In this way, components with non-heat-resistant materials around the intended weld seam, for example, in particular with seals, can still be welded together, which can be damaged in other welding methods.

Also, oxidation on the built-in surface sections of the cylinder liner and of the closing part, in particular in the vicinity of the weld seam, which would otherwise have to be removed in a costly manner according to the prior art, is avoided.

Furthermore, it is advantageous to reduce thermal stresses in the connection partners of the welded connection, since only a relatively small amount of section energy (energy quantity related to the length of the weld seam) has to be expended by means of laser welding.

A further advantage is that the course extension, the weld depth and the angle of the laser circumferential weld can be determined to a maximum extent by the displacement, the segment energy and the angle of the laser beam relative to the working cylinder to be produced. In particular, the course extension and the angle can be calibrated in a targeted manner by changing the position of the laser relative to the connection partner.

In a particularly preferred first configuration of the working cylinder according to the invention, the working cylinder is embodied as a double-acting working cylinder and is designed as a differential working cylinder.

In this configuration, the first closure member is configured as a leading closure member and the second closure member is configured as a bottom closure member. Thus, the cylinder liner first end is referred to herein as the lead side cylinder liner end and the cylinder liner second end is referred to herein as the bottom side cylinder liner end. Thus, a first laser circumferential weld is provided between the guide closure part and the guide-side cylinder liner end, and a second laser circumferential weld is provided between the base closure part and the base-side cylinder liner end.

In the differential cylinder, a piston unit has a piston and a piston rod. For the construction of the piston unit thus constructed, reference is made to the description above relating to the working cylinder.

The piston of the piston unit is arranged in the cylinder interior and thereby divides the cylinder interior into a piston bottom working chamber, which is also designated as the piston bottom chamber, and a piston rod working chamber, which is also designated as the piston rod chamber. The surface of the piston that is effective in the piston bottom space is larger on the piston bottom side surface of the piston than on the rod space side surface of the piston. The force acting on the piston base space side is therefore greater than the force acting on the piston rod space side when the pressure of the pressure medium is the same. The force acting on the piston is transmitted from the cylinder interior to the outside by means of a piston rod, which for this purpose passes through the guide closure element in a sliding manner.

In a particularly preferred second configuration of the working cylinder according to the invention, the working cylinder likewise appears as a double-acting working cylinder, but it is configured here as a synchronous cylinder.

In the synchronization cylinder according to this advantageous variant, the first closing element is designed as a guide closing element, as in the case of the differential operating cylinder. In addition, it is particularly characteristic that the second closing element is likewise designed as a further guide closing element. The guide closing part and the further guide closing part are also referred to collectively hereinafter as guide closing parts. Thus, a first laser girth weld is provided between the guide closure member and the cylinder liner first end, and a second laser girth weld is provided between the other guide closure member and the cylinder liner second end.

The piston unit here likewise has a piston and a piston rod. The piston is disposed within the cylinder interior chamber and divides it into a piston rod first working chamber and a piston rod second working chamber. For this purpose, the piston rod projects beyond the piston on both axial sides and is guided out of the piston interior on both sides from the piston interior through the closure element, both closure elements being present here as guide closure elements. Thus, the piston rod is slidingly passed through the two guide closure members.

The two piston rod working chambers have the same cross section and the piston thereby has effective surfaces of the same size on both sides for the pressure medium. The force acting on the piston and the length of the working path performed by the piston are the same, irrespective of whether a specific pressure flow of the pressure medium, depending on pressure and volume, loads the first piston rod working chamber or the second piston rod working chamber. Because of the same ratio in both operating directions, the synchronization cylinder is usually also used as a steering cylinder and is therefore also referred to as a steering cylinder.

According to a further variant, the working cylinder is designed as a plunger cylinder. It acts here as a single-acting working cylinder.

According to this variant, the first closing part is configured as a guide closing part and the second closing part is configured as a base closing part. The cylinder liner first end is a leading side cylinder liner end and the cylinder liner second end is a bottom side cylinder liner end. Thus, as in the case of a differential cylinder, a first laser circumferential weld is provided between the guide closure part and the guide-side cylinder liner end, and a second laser circumferential weld is provided between the base closure part and the base-side cylinder liner end.

In the plunger cylinder, a piston unit is configured by a cartridge type piston. A barrel piston is disposed in the cylinder chamber. Only one working chamber is formed in the cylinder interior. The cartridge piston slidably passes through the guide closure member. When the working chamber is acted upon by the pressure flow of the pressure medium, the cartridge piston is pushed in the axial direction as a function of the volume of the introduced pressure flow and executes a retraction movement. Whereas the drive-in movement is caused by an externally acting force in the opposite direction.

According to an advantageous variant, the working cylinder is characterized in that an annular first sealing ring is arranged in the cylinder interior between the first closing part and the cylinder liner inner wall of the cylinder liner at a first end of the cylinder liner axially spaced apart from the first laser circumferential weld seam, the first sealing ring forms a pressure-isolated ring first section arranged between the annular first sealing ring and the first laser circumferential weld seam, and/or an annular second sealing ring is arranged in the cylinder interior between the second closing part and the cylinder liner inner wall of the cylinder liner at a second end of the cylinder liner axially spaced apart from the second laser circumferential weld seam, the second sealing ring forms a pressure-isolated ring second section arranged between the annular second sealing ring and the second laser circumferential weld seam.

According to this variant, an annular sealing ring is arranged upstream of the at least one laser girth weld. Preferably, an annular sealing ring is arranged upstream of each of the two laser circumferential welds. The annular sealing ring is also referred to as an O-ring hereinafter.

On the inside of the cylinder chamber, an O-ring separates the ring section upstream of the respective laser circumferential weld from the remaining cylinder chamber in a pressure-tight manner. It has surprisingly been found that the segment energy can be adjusted to a lesser extent by configuring the laser girth weld, so that the thermally sensitive O-ring is likewise not damaged in the vicinity of the laser girth weld. The vicinity refers to the axial distance between the laser girth weld and the O-ring that is less than the inner diameter of the cylinder liner. The O-ring brings about that the ring section is separated from the operating pressure of the pressure medium. As a result, the axial section of the cylinder liner is not acted upon directly in front of or on the laser circumferential weld by the working pressure of the pressure medium, and is therefore no longer subject to buckling loads. The otherwise occurring radial loading of the laser circumferential weld is thereby likewise advantageously avoided in a very simple manner. More precisely, only axial loads are present. The axial load is based on the fact that the operating pressure of the pressure medium acts on the base surface of the respective closure element. Multiaxial loading of the laser circumferential weld and multiaxial material stresses are thereby advantageously avoided.

At the same time, what is achieved by the upstream O-ring is that the at least one working chamber, or depending on the type of working cylinder, both working chambers are likewise protected from contamination on both sides in the O-ring. Any emissions that may occur during laser welding, or particles that can be detached from the connection partners in the region of the laser weld, are prevented in the individual ring segments from being transferred into the working chamber by the O-rings.

According to a further advantageous variant, the laser circumferential weld has a laser circumferential weld depth, the ratio of which to the wall thickness of the cylinder liner is 1.1 to 2.5.

When the laser girth weld does not extend perpendicularly through the cylinder liner wall, the laser girth weld depth is greater than the thickness of the cylinder liner wall.

The connection between the closure parts is thereby particularly advantageously more stable, since the force transmission in the weld seam is distributed over a larger area and is thereby optimized.

This yields the further advantage that the wall thickness of the cylinder liner can be further reduced for specific applications.

According to this advantageous variant, it is furthermore possible, also in the case of a substantially vertical alignment of the weld seam, to design the laser circumferential weld seam to a greater depth than the wall thickness of the cylinder liner, in that the laser circumferential weld seam is machined into the closure part to a greater depth than the cylinder liner thickness. Whereby a more deeply situated weld root occurs. The laser girth weld depth preferably has at least 1.2 times the cylinder liner thickness. It has surprisingly been found that an increase in the load-bearing capacity of the circumferential weld is achieved in the closure part by the seam change thus produced.

According to a further advantageous variant, the laser circumferential weld has an inclined laser circumferential weld center axis. According to the same advantageous variant, the laser circumferential weld center axis encloses a laser circumferential weld inclination angle alpha with the main longitudinal axis of the cylinder liner, wherein alpha is 20 to 70 degrees.

The laser circumferential weld central axis extends centrally through the laser circumferential weld and divides the cross section of the laser circumferential weld into identical portions. When the laser circumferential weld center axis extends to the main longitudinal axis of the cylinder liner, which extends centrally along the cylinder liner, the laser circumferential weld center axis encloses an angle with the main longitudinal axis. This angle is the laser girth weld inclination angle alpha.

The laser fillet angle alpha is between 20 and 70 degrees, thereby producing a ratio of the laser fillet depth to the cylinder liner wall thickness of 1.1 to 2.5.

By means of the greater depth of the laser circumferential weld and the established central axis of the circumferential weld, the forces are better distributed in the presence of loads by means of the angle and the action surface of the acting forces.

According to a further advantageous variant, at least one closing part has an axially open, annular, concave receiving contour, in which the cylinder liner engages, wherein the receiving contour overlaps the cylinder liner in the radial direction and the circumferential weld angle alpha is 110 to 160 degrees. A tilt exceeding 90 degrees is also referred to as a negative tilt hereinafter.

An axially open, annular, concave receiving contour is provided by a ring groove in the respective closure element, which receiving contour has a radial side wall. The side wall arranged radially on the outside is inclined and conical. The concave receiving contour thus forms a radial overlap

The side walls arranged radially inside are preferably not inclined and preferably form a cylindrical shape. The cross section of the contour of the receptacle thereby preferably corresponds to a concave wedge. The cylinder liner is formed on the respective cylinder liner end in accordance with the receptacle contour and has, for this purpose, an inclined annular surface, the inclination of which corresponds to the inclination of the outer radial side wall of the receptacle contour. The cross section of the wall of the cylinder liner end thereby preferably corresponds to a wedge shape, which fits fittingly into the receptacle contour.

The laser circumferential weld is provided between the inclined annular surface of the illustrated receptacle contour and the inclined annular surface of the cylinder liner. The angle of inclination of the laser circumferential weld corresponds here to the angle of inclination of the two inclined annular surfaces.

It has been found that three advantageous effects are simultaneously achieved by this variant by means of the same method. First, by radially overlapping the cylinder liner, a form-locking absorption of the buckling forces caused by the operating pressure of the pressure medium is achieved. The positive absorption of the buckling forces acting in the radial direction relieves the load on the laser circumferential weld seam, so that the material-bound force transmission at the laser circumferential weld seam is actually only for axial forces. Secondly, the tilting allows, without additional measures, the circumferential weld seam depth to exceed the cylinder liner wall thickness and thus allows greater force transmission. Thirdly, an assembly advantage is simultaneously achieved, since the cylinder liner and the corresponding closing part are automatically centered during the axial feed movement.

By way of a further advantageous variant, at least one of the laser circumferential welds is arranged axially at the end face and the circumferential weld inclination angle alpha is 180 degrees.

Thereby, the laser circumferential weld has a cylindrical shape and is thus arranged radially between the cylinder liner and the corresponding closing part.

This variant has the particular advantage that no special machining of the annular end face on the cylinder liner is required. More precisely, only the edge of the inner surface of the cylinder liner forms the contact surface with the corresponding closing part and thereby forms the surface to be welded for the laser circumferential weld. Furthermore, corresponding closure elements without radial steps can be advantageously formed. The outer diameter of the closing element only has to correspond to the inner diameter of the cylinder liner, whereby a significant material saving is achieved. Furthermore, a small precision cylinder liner is necessary when constructing the cylinder liner length, since the exact spacing of the two closing parts can be adjusted exactly when joining.

According to a further advantageous variant, the circumferential weld angle is 90 °. This variant has the advantage on the production side that the annular end face formed by cutting can already be used as a contact surface on the cylinder liner for contacting the corresponding closing element without further work steps.

It is generally true that the different advantageous variants of the configuration of the laser weld seam are not fixedly connected to a specific cylinder type. Furthermore, different configurations of the laser circumferential weld can also be combined on one and the same working cylinder.

According to the invention, the method for producing a working cylinder has the following method steps:

a) joining a cylinder liner, a first closing member, a second closing member and a piston unit into a pre-structural assembly

b) Forming a fixed relative positional relationship of the cylinder liner, the first closing member and the second closing member

c) Laser welding of the cylinder liner to the first closure member is performed to form a first laser circumferential weld, and laser welding of the cylinder liner to the second closure member is performed to form a second laser circumferential weld

In method step a), the cylinder liner, the two closing parts and the piston unit are arranged in their final position. The components so arranged are referred to hereinafter as pre-construction assemblies.

The piston unit is inserted into the first closing part in this way and is introduced into the cylinder liner.

A first closure member is connected to the cylinder liner first end and a second closure member is connected to the cylinder liner second end.

Preferably, the entire assembly is preassembled in its entirety. This means that also temperature-sensitive components, such as seals, for example, are used, as well as a guide in the first closing part which is configured to guide the closing part. The same applies to the guide and the seal on the piston unit. The preassembly is preferably designed such that the working cylinder according to the invention can be completely removed after method step c), i.e. after welding. Method steps such as external surface finishing, in particular coating, can also be followed.

In method step b), the cylinder liner and the closure part of the pre-construction assembly are temporarily fixed and are thus fixed in their positional relationship to one another. In this method step, the relative position of the cylinder liner and the closing element corresponds here to the relative position of these components in the finished working cylinder.

The closing elements are preferably designed in such a way that they are guided along the main longitudinal axis of the cylinder liner in the final position to the cylinder and are fixed by the force applied. This is preferably achieved by precisely matching the respective configurations of the cylindrical section of the cylinder liner and the axial contact surface of the closing member.

The force loading along the main longitudinal axis of the cylinder liner is preferably achieved by inserting the chuck and the hollow spindle (or similar fastening element) of the machine in an opposing manner. The working cylinder to be produced with a high slenderness ratio is preferably additionally guided by the support.

With this device, the pre-construction assembly can preferably be rotated about the main longitudinal axis of the cylinder liner. A temporary fixing is also possible, in which case a rotation of the pre-construction assembly is no longer specified.

The cylinder liner and the two closure parts of the pre-construction assembly are welded together in method step c). The method steps are carried out according to the invention by means of a laser welding method.

During welding, the pre-construction assembly is preferably rotated about the main longitudinal axis of the cylinder liner. The laser emitter is here arranged stationary around the pre-structural assembly. In a further variant of the method step, the pre-structure assembly is arranged in a stationary manner and the laser emitter is actively moved around the pre-structure assembly in order to produce the laser girth weld. The axial force application is preferably maintained during the entire method step c), so that deformations of the connection partners with respect to one another due to thermal stresses are advantageously avoided.

In both variants, a first laser girth weld is produced between the first closure part and the cylinder liner and a second laser girth weld is produced between the second closure part and the cylinder liner.

The two laser circumferential welds join the connection partners of the pre-construction assembly together in a material-locking and irreversible manner. The term irreversible means that it is not possible to uncorrupt the connection.

The production of the first laser circumferential weld and the second laser circumferential weld can be carried out in succession or simultaneously by means of a plurality of laser heads. The welding work is preferably carried out by a fully automatic welding robot in the laser welding device. The welding device preferably operates under protective gas conditions or under partial vacuum conditions.

The manufacturing method is characterized in particular in that according to method step c), there is no longer an access to the cylinder interior. If the closing part is welded to the cylinder liner according to the prior art, there is the problem that oxidation occurs on the inner surface sections of the respective closing part and of the cylinder liner, in other words on the surface sections of the cylinder interior to be formed, which oxidation must be removed again in a further working step. Furthermore, according to the prior art, for example, the seal and the guide can only be inserted into the first closure part, which is designed as a guide closure part, after cooling has taken place, since they could otherwise be thermally damaged.

The production method according to the invention shows a solution according to which welding with inserted heat-sensitive components, such as seals and guides, can also be carried out without subsequent access to the inner surface section and without cleaning thereof.

It has surprisingly been found that by laser welding with a small weld seam width, a small introduced thermal energy (segment energy) per weld seam length, together with a greater welding speed, a high temperature gradient in the pre-structural assembly can be achieved, so that a large part of the thermal energy can be conducted away directly again through the surface surrounding the weld seam, and at the same time the temperature at the inner surface and at the heat-sensitive components, such as seals and guides, can be kept low, so that neither oxidation of the inner surface nor thermal damage to the heat-sensitive components occurs. Furthermore, thermal stresses in the connection partner are significantly reduced. This provides, surprisingly, a previously impossible production safeguard which allows a complete welding of the differential cylinders, wherein, in addition, the method steps for welding the two closure parts can be carried out simultaneously.

As an advantage, the method according to the invention enables considerable savings in production time, since the machining of the cylinder liner can be dispensed with. Furthermore, the production method according to the invention allows the construction of a cylinder liner having a significantly smaller liner wall thickness than the prior art positively connected working cylinders. The statements made to the meaning of the advantages of the working cylinder according to the invention apply in a corresponding manner also to the advantages of the production method.

The laser welding method therefore has the advantage that energy acts locally on the components of the pre-structured packing in a very restricted manner. Less energy is therefore required for the circumferential weld, which also advantageously results in a lower heat input.

By the high precision of the lasers, they can be calibrated very accurately. In this case, the emission direction of the laser preferably extends along the planned laser circumferential weld center axis, and the laser circumferential weld center axis fork preferably extends along the contact surface of the connection partners of the pre-structural assembly. The laser is designed according to the wavelength, power and operating speed and is used to weld the material of the working cylinder.

According to an advantageous variant, the method according to the invention relates to the production of a differential working cylinder. In this variant, the method is characterized in that the joining is carried out in method step a) in the following manner. A cylinder liner, a first closing member configured to guide the closing member, a second closing member configured to be a bottom closing member, and a piston unit constituted by a piston and a piston rod are joined as a pre-structural assembly of a differential operating cylinder. The engagement is made here such that the piston rod passes slidingly through a first closure member, here present as a guide closure member.

According to another variant, the method involves the production of a synchronization cylinder, also called a steering cylinder. According to this variant, the method is characterized in that, in method step a), a cylinder liner, a first closing part designed as a guide closing part, a second closing part designed as a further guide closing part, and a piston unit formed by a piston and a piston rod are joined to form a pre-assembly of the synchronization cylinder. The engagement is performed in such a way that the piston rod passes through the two closure parts in a sliding manner.

According to a next variant, the manufacturing method according to the invention is implemented for manufacturing a plunger cylinder. For this purpose, the joining is carried out in method step a) in the following manner. The cylinder liner, the first closure member configured as a leading closure member, the second closure member configured as a bottom closure member, and the piston unit configured as a barrel piston are joined as a pre-configured assembly of a plunger cylinder. Here, the cartridge piston passes through a first closing part which is designed as a guide closing part.

According to one advantageous variant, laser welding is carried out in method step c) in order to produce a laser circumferential weld having a circumferential weld inclination angle alpha of 20 to 70 degrees. Here, the laser head is guided at this angle relative to the pre-structured assembly. Thereby realizing the laser circumferential weld inclined at the circumferential weld inclination angle.

According to a further advantageous variant, laser welding is carried out in method step c) in order to produce a laser circumferential weld having a circumferential weld inclination angle alpha of 110 to 160 degrees. For this purpose, at least one of the two closure parts is provided with an axially open annular concave receptacle contour, initially prior to the work step a) involving joining. During the joining process according to working step a), the correspondingly configured cylinder liner end is subsequently joined into the receptacle contour, wherein automatic centering is carried out by means of the corresponding configuration, whereby the accuracy is further advantageously increased.

In this case, the laser head is guided in method step c) at this angle relative to the pre-structured assembly. Thereby realizing the laser circumferential weld inclined at the circumferential weld inclination angle. In the entire method step c), the wedge-shaped engagement section remains unchanged under the action of axial forces, so that deformations caused by thermal stresses during laser welding are avoided, wherein the thermal stresses, although reduced as far as possible, cannot be completely ruled out, and furthermore, a particularly precise, positionally accurate laser welding connection of the connection partners is achieved.

According to a further advantageous variant, method step c) is carried out in such a way that at least one of the laser girth welds is introduced axially at the end face and the girth weld inclination angle alpha is 180 degrees. For this purpose, in method step c), the laser beam is aligned parallel to the main longitudinal axis of the working cylinder.

In method step a), the joining takes place, wherein the exact axial spacing of the two closure parts is set in this case. The basis is that at least one of the closure parts does not have radial projections which determine the axial positional relationship of the two connection partners.

In the method for producing a working cylinder, according to a further advantageous variant, the method steps a) to c) are also applied to at least one stationary module.

A stationary module refers to a component for force transmission from the differential cylinder to a component of the application device. In one popular design, the stent module has a bore, also commonly referred to as an eye, into which a locking element, such as a pin, can be inserted. The locking element connects the stationary die block on the piston rod side to the component of the application device in a form-fitting manner and ensures force transmission during operation. The fastening module can be designed in particular as a universal bearing.

At least one of the fastening modules is preferably a fastening module on the piston rod side. The piston-rod-side fixing module refers to a fixing module provided on the piston unit. There can additionally or alternatively be a bottom-side fixing module. The bottom-side fastening module is a fastening module arranged on the second closing part configured as a bottom closing part. However, it is also possible, when the second closure element is designed as a bottom closure element, to configure the second closure element such that it comprises a fastening module, so that the fastening module is only a section of the overall bottom closure element.

At least one of the fastening sections is made of a weldable material, preferably a metal.

In a first variant of this variant, a piston-rod-side fastening module is provided. In a second variant of this variant, a bottom-side fastening module is provided.

In this case, the joining operation is carried out in method step a), which additionally serves as a counterpart for joining the fixed die block on the piston rod side to the pre-assembly. The thus configured pre-structure assembly is referred to hereinafter as an extended pre-structure assembly.

In method step a), a piston-rod-side fastening module is arranged on the piston rod of the piston unit on the part of the piston rod projecting from the cylinder liner. The bottom-side fastening module is arranged on a second closing element designed as a bottom closing element.

In method step b), according to this advantageous variant, a defined positional relationship of the respective fixing module relative to the associated component is also produced.

The fixation module is temporarily and relatively fixed with respect to the corresponding component of the pre-construction assembly. This temporary fixing is carried out analogously to the already described method. However, additional process means for this fixing can likewise be provided.

According to a first variant of this advantageous variant, the fixed module on the piston rod side is welded together in method step c) so that a fixed module first weld seam is formed.

In method step c), the fixing module on the piston rod side is welded to the piston rod. This is preferably done similarly to the welding of the remaining components of the extended pre-construction assembly. The resulting first weld of the fixing module connects the fixing module on the piston rod side to the piston rod.

According to a second variant of the same variant, in method step c), the bottom closure part is welded to the bottom-side fixed module to form a fixed module second weld seam.

This is done analogously to the welding of the fastening module on the piston rod side. A fixed module second weld joins the bottom side fixed module to the bottom closure member.

Drawings

The invention is further illustrated by way of example with the aid of the following figures:

fig. 1 shows a differential cylinder (overview).

Fig. 2 shows an enlarged portion on the cylinder liner end on the pilot side.

Fig. 3 shows an enlarged portion on the cylinder liner end on the bottom side.

Fig. 4 shows an enlarged view of the laser weld in order to reveal the cross section and the girth weld fillet beta.

FIG. 5 shows a plunger cylinder with a 90 degree weld and with an O-ring disposed upstream.

Fig. 6 shows an enlarged portion of fig. 5 in order to show the O-ring and ring segments.

FIG. 7 shows a synchronized cylinder with a negative-rake weld.

Fig. 8 shows an enlarged portion of fig. 7 to reveal a concave receiver profile.

Fig. 9 illustrates an enlarged portion of fig. 7 in an exploded view.

FIG. 10 shows a telescoping cylinder with a combination of 90 degree weld and oblique seam.

FIG. 11 shows a schematic view of a bottom closure member with a 0 degree weld.

Detailed Description

Fig. 1 shows an overview of an exemplary embodiment of a working cylinder 1 as a differential working cylinder. The differential working cylinder 1 consists of the cylinder liner 2, the first closing part 3, here configured as a guide closing part, the second closing part 4, here configured as a bottom closing part, and the piston unit 5. The piston unit has the piston 5a and the piston rod 5 b.

In this embodiment, the piston-rod-side fastening module 15 is arranged on the piston rod 5b, and the bottom-side fastening module 17 is arranged on the second closing element 4, which is designed as a bottom closing element. The two fixing

modules

15, 17 are each assigned a fixing

15a, 17a, which is not part of the invention and is only shown for a better overview.

The piston unit 5 is arranged in the cylinder interior 8 with respect to the piston 5a and with a section of the piston rod 5b, wherein the piston rod 5b passes slidingly through the first closing member 3 configured as a guide closing member.

The first closing part 3, which is designed as a guide closing part, closes the cylinder liner 2 at the cylinder liner first end 6, in this case at the guide-side cylinder liner end, and the second closing part 4, which is designed as a bottom closing part, closes the cylinder liner second end 7, in this case at the bottom-side cylinder liner end.

The two cylinder liner ends 6, 7 are chamfered and therefore have a larger contact surface contacting the two

closing parts

3, 4. In this embodiment, the two

closure parts

3, 4 are designed in such a way that they can be partially and precisely matched by means of the cylindrical sections into the cylinder liner and can therefore be joined more easily to form the pre-construction assembly.

The main longitudinal axis 14 of the cylinder liner 2 extends centrally and longitudinally through the working cylinder 1.

Fig. 2 shows an enlarged view of the region of the first end 6 of the cylinder liner. The guide-side cylinder liner end is referred to here. The geometric relationship of the annular first laser circumferential weld 9 is shown in particular here. In the case of welding in the present embodiment, the first laser circumferential weld 9 is produced in the form of a ring by means of a laser along the circumferential weld center axis 13. The first laser girth weld extends along the interface between the cylinder liner first end 6 and the first closure member 3. For this purpose, the temporarily fixed pre-construction assembly previously assembled from the cylinder liner 2, the first closing part 3, the second closing part 4, the piston unit 5 and the two fixing

modules

15, 17 is rotated about the main longitudinal axis of the cylinder liner 14 and before the laser. The circumferential weld center axis 13 extends centrally through the annular first laser circumferential weld 9 and, in its extension, encloses a circumferential weld inclination angle alpha with the main longitudinal axis of the cylinder liner 14. The circumferential weld depth 11 is the length of the circumferential weld central axis 13 which extends in the actual laser circumferential weld 9. The circumferential weld depth 11 is greater than the cylinder liner wall thickness 12 due to the angle. The circumferential weld depth corresponds to the chord of the right triangle formed by the circumferential weld, the cylinder liner wall thickness 12 and the vertical.

In this illustration, a first weld seam 16 of the fastening module between the fastening module 15 on the piston rod side and the piston rod 5b is also visible. Like the annular first laser circumferential weld 9, this first fixed module weld is produced by the same laser welding method.

Furthermore, the sliding bearing of the piston rod 5b in the first closing part 3, which is designed as a guide part and has a guide 20 and a seal 19, is also shown.

Fig. 3 shows the region of the cylinder liner end on the bottom side, which is the cylinder liner second end 7, in an enlarged manner.

The structure of the diagram corresponds to the greatest extent to fig. 2. The connection of the second closing part 4, configured as a bottom closing part, to the second end 7 of the cylinder liner is carried out by means of a laser welding method, similarly to the connection of the first closing part 3, configured as a guide closing part, to the first end 6 of the cylinder liner (see fig. 2). Here a second laser girth weld 10 is constructed.

This illustration shows, in addition to fig. 2, the piston 5a and how it divides the cylinder interior 8 into a piston base working chamber 8a and a piston rod working chamber 8 b. The two working

chambers

8a, 8b are acted upon separately from each other by hydraulic pressure medium via fluid connections, as a result of which the working cylinder 1, which is designed as a differential cylinder, is operated.

Similarly to the fastening module 15 on the piston rod side (see fig. 2), the fastening module 17 on the base side is also fastened by means of a laser weld seam, the fastening module second weld seam 18.

The laser weld seam is shown enlarged in fig. 4. Here, a first laser weld 9 between the first end 2 of the cylinder liner and the first closing part 3 is shown, which is exemplary of a laser weld according to the invention.

The first laser weld seam 9 has a circumferential weld seam depth 11 and a circumferential weld seam center axis 13. In this embodiment, the girth weld depth 11 is greater than the cylinder liner wall thickness 12.

The laser weld has a slight taper. If two tangents are made to the edge profile of the laser weld, they intersect and enclose a girth weld turret. The circumferential weld central axis 13 is at the same time the angle bisector of the circumferential weld angle beta and encloses the circumferential weld inclination angle alpha with the main longitudinal axis 14. Furthermore, the circumferential weld mid-axis 13 extends along the contact surface of the cylinder liner first end 6 and the first closing part 3. In this embodiment, the fillet angle alpha is 90 degrees.

Fig. 5 shows an exemplary embodiment of a cylinder embodied as a piston cylinder. The piston unit 5, which is designed as a cylinder piston, is guided in the cylinder liner 2. Furthermore, the piston unit 5 is guided in the first closing part 3, which is configured as a guide closing part. For this purpose, the plunger cylinder has a guide 20. The guide closure element is connected to the cylinder liner 2 at its first cylinder liner end 6 by means of a first laser circumferential weld 9. Opposite the guide closure element, the second closure element 4, which is designed here as a bottom closure element, is connected to the cylinder liner 2 at the cylinder liner second end 7 via the second laser circumferential weld 10. In this embodiment, the two laser girth welds 9, 10 have a girth weld inclination of 90 degrees.

The reference numerals and explanations given for the differential cylinders in fig. 1 are additionally applied.

In the exemplary embodiment according to fig. 5, the plunger cylinder furthermore has an additional annular first sealing ring 21 on the first closing part 3. This additional sealing ring 21 is likewise referred to as an O-ring and is arranged radially between the cylinder liner 2 and the first closing part 3 and provides a pressure-tight seal which separates the annular second laser circumferential weld 10 from the pressure medium in a pressure-tight manner.

The region of the sealing ring 21 (O-ring) on the first closing part 3 of fig. 5 is shown enlarged in fig. 6. Here, the sealing ring 21 (O-ring) is shown in more detail, which is located spatially in the vicinity of the annular first laser girth weld 9. In this embodiment, the sealing ring 21 (O-ring) is made of an elastic polymer. The heat input during laser welding is kept small enough not to damage the sealing ring 21 (O-ring), despite its proximity to the first laser girth weld 9. Viewed in axial direction, a pressure-separated ring segment 22 is located between the sealing ring 21 (O-ring) and the first laser girth weld 9. In this pressure-isolated ring segment 22, the operating pressure of the pressure medium is not applied to the inside of the cylinder liner, so that no force acts in the radial direction from the pressure medium on the cylinder liner 2 in this region. The cylinder liner 2 is thereby not loaded with buckling forces in this region, and the load of the first laser circumferential weld 9 is subtracted.

In this embodiment, the circumferential weld centre axis 13 extends perpendicularly to the main longitudinal axis 14 of the working cylinder 1.

FIG. 7 illustrates a synchronized cylinder with a negative-bias weld. In this synchronization cylinder, the two

closing parts

3, 4 are configured to guide the closing parts. The piston 5a is arranged in the central region of the piston rod 5b in the axial direction, which is guided by the two

closing parts

3, 4.

In this exemplary embodiment, the two cylinder liner ends 6, 7 each enter a recessed receptacle contour 23 in the two

closing parts

3, 4 and are welded together there by means of the laser welding method. The laser circumferential welds 9, 10 are negatively inclined here, which means an opposite inclination of the contact surfaces of the

closing parts

3, 4 and the cylinder liner ends 6, 7 (for example compared to the embodiment according to fig. 1).

An enlarged view of the embodiment of fig. 7 is shown in more detail in fig. 8.

The cylinder liner second end 7 has here entered a wedge-shaped recessed receptacle contour 23 and is welded to the second closing part 4 by means of the second laser circumferential weld seam 10, which is annular.

The circumferential weld central axis 13 and the main longitudinal axis 14 enclose the circumferential weld inclination angle alpha.

The fillet angle alpha here has an angle of more than 90 degrees, in the present example approximately 120 degrees.

Fig. 9 shows the connection partner according to fig. 8 in a schematic exploded view. Fig. 8 shows the cylinder liner first end 6 and the first closure member 3 with the wedge-shaped female receiving profile 23 before engagement. The wedge-shaped re-entrant contour 23 is designed such that it can accommodate the cylinder liner first end 6 and, together with the latter, forms a common contact surface on which the first laser circumferential weld 9 is then arranged. Fig. 9 shows that the concave receiving contour 23 is open in the axial direction in the direction of the cylinder liner 2. The buckling forces acting radially inward on the cylinder liner 2 are absorbed in a positive-locking manner by the radial webs 24. The inclined section of the concave receiving contour 23 is concerned here.

Fig. 10 shows an embodiment as a telescopic cylinder. In contrast to the cylinder types described above, the telescopic working cylinder has a further cylinder liner 2a arranged in the cylinder liner 2 and a further closing member 3 a. The first closing part 3 and the further closing part 3a are configured to guide the closing parts. The further cylinder liner 2a is welded to the further closing part 3a by means of a further annular laser circumferential weld 9 a.

In this exemplary embodiment, a straight laser circumferential weld (circumferential weld inclination angle alpha of 90 degrees) is also combined with an oblique laser circumferential weld (circumferential weld angle alpha <90 degrees). In this embodiment, the first annular laser circumferential weld 9 is formed on the first closing part 3 as an oblique laser weld, a further annular laser circumferential weld 9a is formed on the further closing part 3a as an oblique laser weld, and the second annular laser circumferential weld 10 is formed on the second closing part 10 as a straight laser weld.

Fig. 11 shows a schematic view of a part of an embodiment in which the second laser girth weld 10, which is annular, extends parallel to the main longitudinal axis.

The second closing element 4, which is designed as a bottom closing element, is surrounded in the radial direction by the second cylinder liner 2. In this exemplary embodiment, the annular surfaces of the second closing part 4 and the cylinder liner 2 form a common end surface. It is also possible for one of the connection partners to be axially forward-projecting or backward-projecting relative to the other connection partner. The circumferential weld central axis 13 does not intersect the main longitudinal axis 14. The fillet angle alpha of the circumferential weld is 0 degree.

List of reference numerals

1 fixed module of working cylinder 17 bottom side

2 Cylinder liner 18 fixed Module second weld

2a further cylinder liner 19 seal

3 first closing member 20 guide

3a further closing member 21

4 second closure member 22 pressure separated Ring segments

5 concave receiving section contour of piston unit 23

5a radial overlap of the piston 24

Inclination angle alpha of alpha circumferential weld of 5b piston rod

Beta girth weld angle beta of first tail end of 6 cylinder liner

7 cylinder liner second end

8 cylinder inner chamber

8a piston bottom working chamber

8b piston rod working chamber

9 first laser girth weld of annular shape

10 annular second laser girth weld

11 girth weld depth

Wall thickness of 12 cylinder liner

13 ring weld central axis

14 main longitudinal axis

15 piston rod side fixing module

15a piston rod side fixing pin of fixing module

16 fixed module first weld

Claims

1. A cylinder (1) having a cylinder liner (2), a first closing member (3), a second closing member (4), and a piston unit (5),

wherein the cylinder liner (2) has a cylinder liner first end (6) and a cylinder liner second end (7),

wherein the first closing part (3) is arranged on the cylinder liner first end (6),

wherein the second closing part (4) is arranged on the cylinder liner second end (7),

wherein the cylinder liner (2) and the closing parts (3, 4) form a cylinder inner chamber (8),

wherein the piston unit (5) forms at least one working chamber in the cylinder interior (8),

wherein the piston unit (5) slidingly passes through the first closing part (3),

it is characterized in that the preparation method is characterized in that,

the first closing part (3) is connected to the cylinder liner (2) by means of an annular first laser circumferential weld seam (9) in a material-locking manner, and the second closing part (4) is connected to the cylinder liner (2) by means of an annular second laser circumferential weld seam (10) in a material-locking manner,

and the laser circumferential welds (9, 10) each form a fluid-tight sealing plane (10).

2. Working cylinder (1) according to claim 1,

it is characterized in that the preparation method is characterized in that,

the working cylinder (1) is double-acting and is constructed as a differential working cylinder,

wherein the first closing part (3) is configured as a guide closing part and the second closing part (4) is configured as a base closing part,

wherein the cylinder liner first end (6) is a guide-side cylinder liner end and the cylinder liner second end (7) is a base-side cylinder liner end,

wherein the piston unit (5) has a piston (5a) and a piston rod (5b),

wherein the piston (5a) is arranged in the cylinder inner chamber (8) and divides the cylinder inner chamber (8) into a piston bottom working chamber (8a) and a piston rod working chamber (8b), and wherein the piston rod (5b) slidingly passes through the guide closure member (3).

3. Working cylinder (1) according to claim 1,

it is characterized in that the preparation method is characterized in that,

the working cylinders (1) are double-acting and are constructed as synchronized cylinders,

wherein the first closing part (3) is configured as a guide closing part and the second closing part (4) is configured as a further guide closing part,

wherein the piston unit (5) has a piston (5a) and a piston rod (5b),

wherein the piston (5a) is arranged in the cylinder inner chamber (8) and divides the cylinder inner chamber (8) into a piston rod first working chamber and a piston rod second working chamber, and wherein the piston rod (5b) slidingly passes through the guide closing member and the further guide closing member.

4. Working cylinder (1) according to claim 1,

it is characterized in that the preparation method is characterized in that,

the working cylinder (1) is single-acting and is constructed as a plunger cylinder,

wherein the piston unit (5) is constructed by a cartridge piston,

wherein the cartridge piston is arranged in the cylinder inner chamber (8) and a working chamber is configured in the cylinder inner chamber (8), and wherein the cartridge piston slidingly passes through the guide closure member (3).

5. Working cylinder (1) according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

an annular first sealing ring (21) is arranged in the cylinder interior (8) between the first closing part (3) and the cylinder liner inner wall of the cylinder liner (2) at a cylinder liner first end (6) of the cylinder liner axially spaced apart from the first laser circumferential weld (9), the first sealing ring forming a pressure-isolated ring first section (22) which is arranged between the annular first sealing ring (21) and the first laser circumferential weld (9) and/or an annular second sealing ring in the cylinder interior (8) between the second closing part (4) and the cylinder liner inner wall of the cylinder liner (2) at a cylinder liner second end (7) of the cylinder liner axially spaced apart from the second laser circumferential weld (10), the second sealing ring forming a pressure-isolated ring second section, the second ring section is arranged between the second annular sealing ring and the second laser circumferential weld (10).

6. A working cylinder (1) according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the laser circumferential welds each have a circumferential weld depth (11),

wherein the ratio of the circumferential weld depth (11) to the cylinder liner wall thickness (12) is 1.1 to 2.5.

7. Working cylinder according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the laser circumferential welds (9, 10) are respectively provided with a circumferential weld central axis (13),

wherein the circumferential weld mid-axis (13) and the main longitudinal axis (14) of the cylinder liner (2) enclose a circumferential weld inclination angle alpha, wherein alpha is between 20 and 70 degrees.

8. Working cylinder (1) according to one of the preceding claims 1 to 6,

it is characterized in that the preparation method is characterized in that,

at least one closing part (3, 4) has an axially open, annular, concave receiving contour into which the cylinder liner engages, wherein the receiving contour overlaps the cylinder liner in the radial direction and the circumferential weld angle alpha is 110 to 160 degrees.

9. The working cylinder (1) according to any one of the preceding claims 1 to 6,

it is characterized in that the preparation method is characterized in that,

at least one of the laser girth welds is axially disposed at an end face and the girth weld inclination angle alpha is 180 degrees.

10. A method for producing a working cylinder (1),

wherein the working cylinder (1) is constructed according to any one of claims 1 to 8,

it comprises the following steps:

a) joining the cylinder liner (2), the first closing part (3), the second closing part (4) and the piston unit (5) into a pre-structural assembly,

b) forming a fixed relative positional relationship between the cylinder liner (2), the first closing member (3) and the second closing member (4)

c) -carrying out a laser welding of the cylinder liner (2) with the first closing part (3) so as to form the first laser girth weld (9), and-carrying out a laser welding of the cylinder liner (2) with the second closing part (4) so as to form the second laser girth weld (10).

11. Method for manufacturing a working cylinder (1) according to claim 10,

it is characterized in that the preparation method is characterized in that,

in the method step a), the cylinder liner (2), a first closing part (3) designed as a guide closing part, a second closing part (4) designed as a base closing part and a piston unit (5) consisting of the piston (5a) and a piston rod (5b) are joined to form a pre-construction assembly of a differential working cylinder, wherein the piston rod (5b) passes through the first closing part (3) in a sliding manner.

12. Method for manufacturing a working cylinder (1) according to claim 10,

it is characterized in that the preparation method is characterized in that,

in the method step a), the cylinder liner (2), a first closing part (3) designed as a guide closing part, a second closing part (4) designed as a further guide closing part and a piston unit (5) consisting of the piston (5a) and a piston rod (5b) are joined to form a pre-assembly of the synchronization cylinder, wherein the piston rod (5b) passes through the two guide closing parts (3, 4) in a sliding manner.

13. Method for manufacturing a working cylinder (1) according to claim 10,

it is characterized in that the preparation method is characterized in that,

in the method step a), the cylinder liner (2), the first closing part (3) configured as a guide closing part, the second closing part (4) configured as a bottom closing part and the piston unit (5) configured as a cartridge piston are joined to form a pre-construction assembly of a plunger cylinder.

14. Method for manufacturing a working cylinder (1) according to any of the preceding claims 9 to 12,

it is characterized in that the preparation method is characterized in that,

the working cylinder (1) is constructed according to any one of claims 1 to 7, and

laser welding is carried out in step c) of the method in order to form a laser circumferential weld seam (9, 10) having a circumferential weld seam inclination angle alpha of 20 to 70 degrees.

15. A method for producing a working cylinder (1),

it is characterized in that the preparation method is characterized in that,

constructing the working cylinder (1) according to any one of claims 1 to 6 and claim 8,

laser welding is carried out in step c) of the method in order to form a laser circumferential weld seam (9, 10) having a circumferential weld seam inclination angle alpha of 110 to 160 degrees.

16. A method for producing a working cylinder (1),

it is characterized in that the preparation method is characterized in that,

constructing the working cylinder (1) according to any one of claims 1 to 6 and claim 9,

in step c) of the method, laser welding is carried out in order to form a laser circumferential weld (9, 10) which is arranged axially and at the end face and has a circumferential weld inclination angle alpha of 110 to 160 degrees.

17. Method for manufacturing a working cylinder (1) according to any of the preceding claims,

it is characterized in that the preparation method is characterized in that,

in the method step a), a piston-rod-side fastening module (15) is also joined to form the pre-assembly,

in the method step b), a fixed relative position of the fixing module (15) on the piston rod side is also established, and

in step c) of the method, the piston rod (5b) is welded to the piston-rod-side fastening module (15) in order to form a fastening-module first weld seam (16).

18. Method for manufacturing a working cylinder (1) according to any of the preceding claims,

it is characterized in that the preparation method is characterized in that,

in the method step a), a bottom-side fastening module (17) is also joined to form the pre-assembly,

wherein in method step b) a fixed relative position of the bottom-side fastening modules (17) is additionally formed,

wherein in step c) the second closing part (4) is welded to the bottom-side fastening module (17) to form a fastening module second weld seam (18).